test = 4
#start of def
def change():
test = 5
#end
change()
print test
Why doesn't it print 5? Can anyone explain this to me? Btw, test = 5 is indented, the forum won't let me indent for some reason
Ronnicus
0
Newbie Poster
Recommended Answers
Jump to PostMy code:
test = 4 def change(): test = 5 print test change() print testMy output:
>>> 4 4Note: I used Python 2.6 here. I tried it with 3.1.1 (with correct syntax) and got the same result.
Jump to PostRonnicus,
please put your code into code tags like this:[code]
... your Python code here ...[/code]
If your function changes a value you want to use, you have to use return. Here is your correct approcach ...
test = 4 def change(): test …
All 8 Replies
Mouche
My code:
test = 4
def change():
test = 5
print test
change()
print testMy output:
>>>
4
4Note: I used Python 2.6 here. I tried it with 3.1.1 (with correct syntax) and got the same result.
vegaseat
1,735
DaniWeb's Hypocrite
Team Colleague
Ronnicus,
please put your code into code tags like this:
[code]
... your Python code here ...
[/code]
If your function changes a value you want to use, you have to use return. Here is your correct approcach ...
test = 4
def change():
test = 5
return test
print test # 4
test = change()
print test # 5
Mouche
Oh my bad. I thought he was getting "5" for some reason.
Ronnicus
0
Newbie Poster
Why do you have to use return? Couldn't it be a void method that sets test = 5? Why wouldn't that affect the actual value of test?
Mouche
The test variable in the function is in a different scope. It is local to the function, so it does not affect the one outside of the function. It's also not good practice to make the test variable global so that it could be affected by the function. That can cause confusion when things get more complicated.
Ronnicus
0
Newbie Poster
Why is the test in the function local? I meant to have it change the one outside, how would I do so without returning the variable?
jcao219
18
Posting Pro in Training
Why is the test in the function local? I meant to have it change the one outside, how would I do so without returning the variable?
You'd do global test ,
which is a bad idea, since it is evidence for bad code structure.
Scopes make Python a clean and professional language, any other OO language has them, too.
bumsfeld
413
Nearly a Posting Virtuoso
If variables inside functions wouldn't be local, any code would be just loaded with hard to trace bugs!
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